Regulator for electric furnaces.



F. W. SMITH.

REGULATOR FOR ELECTRIC FURNACES.

APPLICATION FILED JAN. 5.191s.

1,282,478. Patented Oct. 22, 1918.

a V a a ESSES- IINVENTOR.

ATTORNEY UNITED STATES PATENT OFFICE.

FRANK W. SMITH, OF WESTF IELD, NEW JERSEY.

REGULATOR For. ELECTRIC manners.

To all whom it may concern:

Be it known that I, FRANK W; SMITH, a citizen of the United States, residing at lVestfield, in the county of Union and State of New Jersey, have invented a certain new and useful Regulator for Electric Furnaces,

. of which the following is a specification.

My present invention relates to a regulator for electric furnaces, particularly arc furnaces, of the type in which the position of the electrodes or movable elements of the furnace is automatically adjusted in response to variations of current in the electrode circuits either above or below a predetermined normal value, the object being to" ment, and combination of parts hereinafter described and particularly pointed out in the annexed claims.

- The accompanying drawing, in its sin gle figure, illustrates, more or less diagrammatically, a regulator embodying my invention as applied to one of the electrodes of a wellknown alternating current are furnace, it being understood that a similar regulating device may be associated with each of the other furnace electrodes.

Referring to this drawin the furnace comprises a suitable receptac e 1 containing the usual conductive charge 2 and an electrode 3 (with others, not shown,) connected to the supply wire 4 of an alternating current supply system, the other electrodes being in like manner connected to the supply wires 5 and 6. A fluid motor 7 which may be a compressed air or other commercial motor of any suitable construction, is operatively connected with the electrode by means, as here shown, of a pivoted lever 9 which at one end is suitably connected with the piston rod 8 of the motor and at its other end is connected to a link IOattached, preferably Specification of Letters Patent.

Patented Oct. 22, 1918.

Application filed January 5, 1918. Serial No. 210,497.

adjustably, to the upper end of and supportmg the electrode. The motor is operated by motive fluid from a supply pipe 11, connected with a-storage tank 12 or other source of supply, admitted either to the upper end of'its cylinder through a pipe 13 or to its lower end through a pipe 14 under the control of a valve 15, of an well-known type, which at the same time t at it connects pipe 13 with the supply pipe will connect pipe 14 with an exhaust 16, preferably provided with a valve as shown to regulate and adjust the size of theexhaust opening, and, re-

versely, will connect pipe 13 with the exhaust when pipe 14 is connected with the supply-pipe. This valve is actuated, through a lever-arm 17 which is restored to and normally held by centering springs 18 and 19 in a from 0th supply and exhaust, either manually, wh'enever found desirable, or automatically by means of one or the other of two magnets 20 and 21. The circuits through the actuating coils of these magnets, adapted to be connected across the supply wires 4 and 6 and including wires 22, 23, 24 and 22, 25, 26, respectively, are in turn controlled by a relay which comprises a movable switch-contact 27 in electrical connection with circuit wire 22, two fixed contacts 28 and 29 connected respectively with circuit osition adapted to cut off the motor wires 23 and 25, and operating magnet 30 whose coil is in closed circuit with a trans former coil 31 on the supply-wire 4, and,

preferably,.an adjustable spring 32 adapted tion of the several parts of the apparatus will be fully understood by those skilled in the art.

The parts of the regulating device are so adjusted that, when t e current in the supply wire 4 is of predetermined normal value,

. the movable contact of'the relay will be held in position intermediate the two fixed contacts thereby cutting both magnets 20 and 21 out of circuit, the valve of the motor will be held by the centering springs in position to close the two ends of the motor cylinder both to the supply-pipe and to the exhaust, and the piston of the motor and consequently the electrode will remain stationary. \Vhenever, however, the currentin the 5 supply wire falls below such value, owing to a lengthening of the arc due to the wearing away of the electrode or to any other cause, the weakening of the magnet of the relay will permit its movable contact to drop against the lower contact 25. This closes the actuating circuit of magnet 21, which, provided there is current on the supply wires 4 and 6, will immediately draw down the lever-arm and so move the valve as to connect the lower end of the motor cylinder with the supply pipe and its upper end with the exhaust. The piston of the motor is accordingly moved upward, and the electrode is moved downward and shortens the are. at a. rate determined. for example, by the adjustment of the valve in the exhaust. Or, reversely, if for any reason the current in the electrode circuit rises above normal, the electrode will be raised and the arc lengthened since the magnet 20 will be energized by the action of the relay and will connect the upper side of the motor cylinder with the supply pipe. In either event, as soon .as the length of the arc has been so adjusted as to restore the electrode current to normal, the relay will open the circuit of the magnet 20 or 21, as the case may be, and the motor will be shut off and will instantly stop without overrunning. The centering springs 18 and 19, it will be seen, also serve as a means for automatically shutting off the motor and stopping the movement of the electrode whenever there is a failure of voltage on the supply wires, while the valve in the exhaust provides a convenient means for regulating the rate of travel of the motor piston either to speed it up, which may be found desirable when a short used-up electrode is to be replaced with a new one and under other operating conditions, or to slow it down. It is, of course, to be understood that the invention is not limited to any feature or detail of the specific regulating device here- 0 in illustrated and described, except as set forth .in the appended claims.

What I claim, as new, and desire to secure by Letters Patent, is-

1. In combination, an electric circuit, a.

movable element therein, a fluid motor operatively connected with the movable element, electromagnetic means normally cut out of circuit for controlling the motor, and means responsive to changes in the electrical condition of the circuit for controlling said electromagnetic means.

2. In combination, an' electric circuit, a movable element therein, a fluid motor 0peratively connected with the movable element, two electromagnets adapted when energized to start the motor one in one direction and the other in the other direction, and means controlled by the electrical condition of the circuit for controlling the elec tromagnets. 7 0

3. In combination, an electric circuit,'a movable element therein, a fluid motor operatively connected with said movable element, two electromagnets normally out of circuit and adapted when energized to control the motor, and means responsive to variations in the electrical condition of the circuit for controlling the electromagnets.

4. In combination, an electric circuit, a movable element therein, a fluid motor operatively connected with the movable element, and means responsive to variations in the electrical condition of the circuit for controlling the motor and adapted to automatically shut it off on failure of voltage on the circuit.

5. In combination, an electrode, a supply circuit therefor, means for moving the electrode to adjust the length of the are formed thereby, and electromagnetic means normally cut out of circuit and controlled by the electrical condition of the electrode supply circuit for controlling the electrode moving means.

6. In combination, an electrode, a supply circuit therefor, a fluid motor operatively connected with the electrode and adapted to move it to regulate the length of the are formed thereby, means responsive to varia-. tions in the electrical conditions of the supply circuit for controlling the motor, and means for regulating the speed of operation of the motor.

7. In combination, an electric circuit, a movable element therein, a fluid motor operatively connected with the movable element, and means responsive to variations in the electrical condition of the circuit for controlling the motor and adapted to automatically shut off the motor on failure of voltage in the circuit.

8. A regulator for an electric furnace comprising an electrode, a circuit therefor, a fluid motor adapted to change the position of the electrode, and means operated by cur- 1 rent in the electrode circuit and controlled by variations thereof for controlling the motor.

9. A regulator for an electric furnace comprising an electrode, a circuit therefor, a fluid motor adapted to change the position of the electrode, a valve controlling the motor, electromagnetic means for operating the valve, and means responsive to variations of current in the electrode circuit for controlling said electromagnetic means.

10. A regulator for an electric furnace comprising an electrode, a circuit therefor, a fluid motor adapted to change the position of the electrode, means for regulating the speed of the motor, a valve for controlling the motor, and means responsive to variations in the electrical conditions of the electrode circuit for controlling the valve and adapted to automatically move the valve to shut off the motor on failure of voltage on the electrode circuit.

11. A regulator for an alternating current furnace comprising an electrode, a circuit supplying lternating current thereto, means for adjusting the position of the electrode to lengthen or shorten the arc, and means operated by current in the electrode supply cirv cuit and responsive to variations in the electrical condition thereof for controlling the electrode adjusting means.

12. A regulator for an alternating current are furnace comprising an electrode, a circuit supplying alternating current thereto, a motor adapted to move the electrode to lengthen or shorten the arc, electromagnets energized by current in the supply circuit for controlling the motor, and means actuated by variations in the electrical condition of the supply circuit for controlling the electromagnets.

FRANK W. SMITH. 

